The present invention relates to the field of body cushions, and more particularly to support surfaces consisting of pneumatic devices that promote blood circulation through the muscles bearing body weight.
People confined to a bed and/or wheelchair for prolonged periods or time are at risk for developing pressure sores, which result from excessive pressure applied to the capillaries lying between a bony part of the body and the surface of the bed or scat. In a seated position, the majority of the person""s body weight is supported by a very small area underneath the buttocks. Passive means such as air, gel or foam cushions claim to be the best devices for redistributing the weight of the person sitting on them. Yet neither method is satisfactory in eliminating the pressure on capillaries created as the result of capillaries being pressed against the bony parts of the buttocks when seated. The pressure points where the majority of the weight rests restricts the blood flow through the capillaries.
The creation of a pressure sore requires a combination of two main elements: pressure and time. Thus, pressure in excess of the capillary pressure for a prolonged time creates pressure sores. Reducing the pressure under the capillary pressure in the most vulnerable parts of the buttock requires the application of means that would allow periodical relief, thus allowing an unobstructed flow of blood for short periods of time to the oxygen deprived areas.
Other active pads typically include two sets of inter-spaced transverse inflatable tubular elements, which are alternately inflated and deflated, thus providing alternating pressure relief to the buttock area. Such devices are usually comprised of 4 or 6 tubular elements. An example of such a system is disclosed in U.S. Pat. No. 5,500,965 that uses two sets of elements, each composed of two chambers that inflate and deflate. Alternating between the inflated and deflated tubes results in having the body supported by half of the entire surface, causing a significant increase of pressure, already higher than the capillary pressure, on those body parts supported by the inflated tubes.
However, alternating the pressure on the body part by using large air cells does not effectively alleviate the pressure points to permit proper blood flow through the capillaries and prevent the aforementioned problems.
What is needed is a device that is capable of sequentially relieving the air pressure, in a controlled fashion, with minimum pressure increase on the remaining cells that continue supporting the weight of the body. Such a device should employ smaller air cells that can re-distribute the weight and allow proper circulation across the entire buttocks area when seated. The device should be easily incorporated into existing designs and cost-effective. Furthermore the device should be adaptable to numerous applications such as motor vehicles, buses, trucks, construction equipment, wheelchairs, and all various chair embodiments.
Accordingly, an object of the present invention is a pneumatic cushion consisting of a plurality of air cells constructed of soft, airtight, non-elastic material, mounted on a rigid or semi-rigid base to be installed on a wheelchair, bedside chair or any other support surface.
The present invention is a sequential pressure relief seat for therapeutic treatment of immobile persons to prevent pressure sores and skin break down and promote blood flow comprising an array of airtight cells, tubular in shape, mounted side-by-side in a vertical position upon a rigid base. Their is a layer of foam that encircles the array with the array of air tight cells, so that when the multiple air cells are inflated they form a uniform surface. A power supply is interconnected to furnish electrical power to the air supply unit and the various valves requiring power. An air supply unit provides pressurized air to the array of air cells, and the air supply unit is connected to a battery or AC outlet. There is an electrically operated air valve controlling the direction of the air flow to or from the air cells, with a control means for controlling the inflating and deflating order of the air cells. The control means typically consists of a pressure sensor, a microprocessor, and a memory chip. At least one electronically controlled selector valves directs the air to or from the selected air cells.
The sequential pressure relief seat device is used in a chair, wherein a control case houses the supply unit parts including the air pump, battery, air valve and the control unit parts including the pressure sensor, the microprocessor and the memory chip. A set of selector valves, such as a two eight-way or four four-way or eight two-way or sixteen one-way, electronically controlled to direct the air flow independently to and from each one of the air cells. In a preferred embodiment the plurality of tubular air cells is sixteen or more. One embodiment is for a relief seat that is built with seven or more air cells, the air cells having a square shape, positioned side-by-side to form a xe2x80x9cno gapxe2x80x9d surface when inflated.
The air cells are typically tubular shaped, although they might be designed in any other shape mounted in proximity to each other, to provide an even cushioned surface. Unlike the prior art devices, the air cells are mounted on the base of the cushion in a vertical position, or perpendicular to the base. The number of air cells varies according to the size and shape of the seat and the desired function, however in a preferred embodiment there should be enough cells to properly alleviate pressure and increase blood flow. The matrix of air cells might be enclosed around the perimeter and supported by a frame of foam that conforms to the shape of the chair. Each such air cell is linked at its bottom to an air tube, wherein each tube connects at least one cell to a battery-powered pump that provides pressurized air.
The air, flowing from the pump through the pressure sensor and the tubes, is regulated by one or a number of controllable selector valves that provide three-way positions: closed; open to release air from the cell; open to push air to the cell.
A control unit that includes a microprocessor and memory for storing information relating to pressures within the air cells communicates electronically with the valves to select the appropriate position: closed, open to inflate or open to deflate. The pattern, order and sequence in which the air cells inflate and deflate are pre-programmed and embedded in the microprocessor. The system is set in motion by pressing a single button located in a convenient, easy to reach handle of the chair. The system may include a back-up rechargeable battery to allow mobility and uninterrupted operation in case of electrical power interruption.
Given the relatively small size of its air cells, it is another object of the present invention to provide a pulsating effect resulting in an acceleration of the blood flow through the buttock area.
As described herein, an object of the invention is a sequential pressure relief device for use in seating, comprising a plurality of air cells mounted vertically on a semi-rigid base. The semi-rigid base provides some flexure, however it is also within the scope of the invention to use a rigid base. There is a support layer encircling the plurality of air cells. An air supply unit provides pressurized air to the plurality of air cells and there is an electrically operated valve controlling air flow to the plurality of air cells, with a control means for inflating and deflating selected air cells. Additionally, there is at least one electronically controlled selector valve directing the air to the selected air cells.
A further object is the sequential pressure relief device, wherein the power supply, the electrically operated valve, the control means, and the electronically controlled selector valve are connected to a main ON/OFF switch. The main On/Off switch is chosen from the group consisting of a manual switch, a voice activated switch and a foot operated switch.
A further object is the sequential pressure relief device, wherein the power supply is a DC storage battery. Alternatively, the system can use an AC/DC converter and connect to an AC power source.
Yet an additional object is the sequential pressure relief device, wherein each of the cells have a shape chosen from the group of shapes such as hexagonal prism, cylinder, rectangular prism, and square prism. In one embodiment, each of the cells have diameters of about approximately three inches and each of the cells is approximately three inches in height. Furthermore, in a preferred embodiment the sequential pressure relief device has a minimum of seven air cells.
An object includes the provision of a sequential pressure relief device wherein the control means comprises a microcontroller with or without a memory device. In particular. wherein the memory device is an erasable electronically programmable read only memory with an inflation/deflation sequence. And even more particularly, wherein the sequence can be customized by the user.
And a further object is the provision of a sequential pressure relief device wherein the device is selected from the group consisting of a stationary chair, a lounge chair, a wheel chair, and a seat of a motor vehicle.
An object of the invention is the provision of a sequential pressure relief device for use in a motor vehicle, comprising a plurality of air cells mounted on a rigid base, wherein the cells are perpendicular to the base. There is a support layer encircling the plurality of air cells, providing a uniform surface when in hated. An air supply unit provides pressurized air to the plurality of air cells. And there is an electrically operated valve controlling air flow to the plurality of air cells the control means for inflating and deflating selected air cells is with a memory device having a programmed inflation/deflation sequence for the air cells and at least one electronically controlled selector valve directing the air to and from the selected air cells.
And an even further embodiment is for the sequential pressure relief device, wherein a power supply is from a motor vehicles power system and air supply is generated from a motor vehicle air system. Connecting the system into a vehicle allows the flexibility to use the electrical system, including the battery of the vehicle. The cars also come with air blowing units wherein the seating system can be adapted to supply the required pressurized air supply for the cells from the car air blowing unit.
Another embodiment of the sequential pressure relief device has an inflation/deflation sequence. One example of the inflation/deflation sequence operates using sixteen air cells sequentially inflating a first cell in row two in conjunction with a last cell in row three followed by a last cell in row two in conjunction with a first cell in row three followed by with all four cells in row one followed by four cells in row four. This diagonal inner inflation is just one of the embodiments. Another embodiment for the inflation/deflation sequence operates using sixteen air cells sequentially inflating a first cell in row two in conjunction with a last cell in row two, followed by a first cell in row three in conjunction with a last cell in row three, followed by all four cells in row one, followed by four cells in row four.
Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description. As will be realized, the invention is capable of other and different embodiments. The invention""s several details are capable of modification in various respects without departing from the spirit of the invention.